liblttng-ust-comm/lttng-ust-comm.c

   1 /*
   2  * Copyright (C)  2011 - David Goulet <david.goulet@polymtl.ca>
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License
   6  * as published by the Free Software Foundation; only version 2
   7  * of the License.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  17  */
  18
  19 #define _GNU_SOURCE
  20 #include <limits.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <sys/socket.h>
  25 #include <sys/stat.h>
  26 #include <sys/types.h>
  27 #include <sys/un.h>
  28 #include <unistd.h>
  29 #include <assert.h>
  30 #include <errno.h>
  31
  32 #include <ust/lttng-ust-comm.h>
  33
  34 /*
  35  * Human readable error message.
  36  */
  37 static const char *ustcomm_readable_code[] = {
  38         [ USTCOMM_ERR_INDEX(USTCOMM_ERR) ] = "Unknown error",
  39         [ USTCOMM_ERR_INDEX(USTCOMM_UND) ] = "Undefined command",
  40         [ USTCOMM_ERR_INDEX(USTCOMM_NOT_IMPLEMENTED) ] = "Not implemented",
  41         [ USTCOMM_ERR_INDEX(USTCOMM_UNKNOWN_DOMAIN) ] = "Unknown tracing domain",
  42         [ USTCOMM_ERR_INDEX(USTCOMM_NO_SESSION) ] = "No session found",
  43         [ USTCOMM_ERR_INDEX(USTCOMM_LIST_FAIL) ] = "Unable to list traceable apps",
  44         [ USTCOMM_ERR_INDEX(USTCOMM_NO_APPS) ] = "No traceable apps found",
  45         [ USTCOMM_ERR_INDEX(USTCOMM_SESS_NOT_FOUND) ] = "Session name not found",
  46         [ USTCOMM_ERR_INDEX(USTCOMM_NO_TRACE) ] = "No trace found",
  47         [ USTCOMM_ERR_INDEX(USTCOMM_FATAL) ] = "Fatal error of the session daemon",
  48         [ USTCOMM_ERR_INDEX(USTCOMM_CREATE_FAIL) ] = "Create trace failed",
  49         [ USTCOMM_ERR_INDEX(USTCOMM_START_FAIL) ] = "Start trace failed",
  50         [ USTCOMM_ERR_INDEX(USTCOMM_STOP_FAIL) ] = "Stop trace failed",
  51         [ USTCOMM_ERR_INDEX(USTCOMM_NO_TRACEABLE) ] = "App is not traceable",
  52         [ USTCOMM_ERR_INDEX(USTCOMM_SELECT_SESS) ] = "A session MUST be selected",
  53         [ USTCOMM_ERR_INDEX(USTCOMM_EXIST_SESS) ] = "Session name already exist",
  54         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_NA) ] = "UST tracer not available",
  55         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_EVENT_EXIST) ] = "UST event already exists",
  56         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_SESS_FAIL) ] = "UST create session failed",
  57         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CHAN_FAIL) ] = "UST create channel failed",
  58         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CHAN_NOT_FOUND) ] = "UST channel not found",
  59         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CHAN_DISABLE_FAIL) ] = "Disable UST channel failed",
  60         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CHAN_ENABLE_FAIL) ] = "Enable UST channel failed",
  61         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CONTEXT_FAIL) ] = "Add UST context failed",
  62         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_ENABLE_FAIL) ] = "Enable UST event failed",
  63         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_DISABLE_FAIL) ] = "Disable UST event failed",
  64         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_META_FAIL) ] = "Opening metadata failed",
  65         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_START_FAIL) ] = "Starting UST trace failed",
  66         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_STOP_FAIL) ] = "Stoping UST trace failed",
  67         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_CONSUMER_FAIL) ] = "UST consumer start failed",
  68         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_STREAM_FAIL) ] = "UST create stream failed",
  69         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_DIR_FAIL) ] = "UST trace directory creation failed",
  70         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_DIR_EXIST) ] = "UST trace directory already exist",
  71         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_NO_SESSION) ] = "No UST session found",
  72         [ USTCOMM_ERR_INDEX(USTCOMM_KERN_LIST_FAIL) ] = "Listing UST events failed",
  73         [ USTCOMM_ERR_INDEX(USTCONSUMER_COMMAND_SOCK_READY) ] = "UST consumer command socket ready",
  74         [ USTCOMM_ERR_INDEX(USTCONSUMER_SUCCESS_RECV_FD) ] = "UST consumer success on receiving fds",
  75         [ USTCOMM_ERR_INDEX(USTCONSUMER_ERROR_RECV_FD) ] = "UST consumer error on receiving fds",
  76         [ USTCOMM_ERR_INDEX(USTCONSUMER_POLL_ERROR) ] = "UST consumer error in polling thread",
  77         [ USTCOMM_ERR_INDEX(USTCONSUMER_POLL_NVAL) ] = "UST consumer polling on closed fd",
  78         [ USTCOMM_ERR_INDEX(USTCONSUMER_POLL_HUP) ] = "UST consumer all fd hung up",
  79         [ USTCOMM_ERR_INDEX(USTCONSUMER_EXIT_SUCCESS) ] = "UST consumer exiting normally",
  80         [ USTCOMM_ERR_INDEX(USTCONSUMER_EXIT_FAILURE) ] = "UST consumer exiting on error",
  81         [ USTCOMM_ERR_INDEX(USTCONSUMER_OUTFD_ERROR) ] = "UST consumer error opening the tracefile",
  82         [ USTCOMM_ERR_INDEX(USTCONSUMER_SPLICE_EBADF) ] = "UST consumer splice EBADF",
  83         [ USTCOMM_ERR_INDEX(USTCONSUMER_SPLICE_EINVAL) ] = "UST consumer splice EINVAL",
  84         [ USTCOMM_ERR_INDEX(USTCONSUMER_SPLICE_ENOMEM) ] = "UST consumer splice ENOMEM",
  85         [ USTCOMM_ERR_INDEX(USTCONSUMER_SPLICE_ESPIPE) ] = "UST consumer splice ESPIPE",
  86         [ USTCOMM_ERR_INDEX(USTCOMM_NO_EVENT) ] = "Event not found",
  87 };
  88
  89 /*
  90  *  lttcom_get_readable_code
  91  *
  92  *  Return ptr to string representing a human readable
  93  *  error code from the ustcomm_return_code enum.
  94  */
  95 const char *ustcomm_get_readable_code(int code)
  96 {
  97         if (code == USTCOMM_OK) {
  98                 return "Success";
  99         }
 100         if (code >= USTCOMM_ERR && code < USTCOMM_NR) {
 101                 return ustcomm_readable_code[USTCOMM_ERR_INDEX(code)];
 102         }
 103         return strerror(code);
 104 }
 105
 106 /*
 107  *      ustcomm_connect_unix_sock
 108  *
 109  *      Connect to unix socket using the path name.
 110  */
 111 int ustcomm_connect_unix_sock(const char *pathname)
 112 {
 113         struct sockaddr_un sun;
 114         int fd;
 115         int ret;
 116
 117         /*
 118          * libust threads require the close-on-exec flag for all
 119          * resources so it does not leak file descriptors upon exec.
 120          */
 121         fd = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0);
 122         if (fd < 0) {
 123                 perror("socket");
 124                 ret = fd;
 125                 goto error;
 126         }
 127
 128         memset(&sun, 0, sizeof(sun));
 129         sun.sun_family = AF_UNIX;
 130         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 131         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 132
 133         ret = connect(fd, (struct sockaddr *) &sun, sizeof(sun));
 134         if (ret < 0) {
 135                 /*
 136                  * Don't print message on connect error, because connect
 137                  * is used in normal execution to detect if sessiond is
 138                  * alive.
 139                  */
 140                 goto error_connect;
 141         }
 142
 143         return fd;
 144
 145 error_connect:
 146         close(fd);
 147 error:
 148         return ret;
 149 }
 150
 151 /*
 152  *      ustcomm_accept_unix_sock
 153  *
 154  *      Do an accept(2) on the sock and return the
 155  *      new file descriptor. The socket MUST be bind(2) before.
 156  */
 157 int ustcomm_accept_unix_sock(int sock)
 158 {
 159         int new_fd;
 160         struct sockaddr_un sun;
 161         socklen_t len = 0;
 162
 163         /* Blocking call */
 164         new_fd = accept(sock, (struct sockaddr *) &sun, &len);
 165         if (new_fd < 0) {
 166                 perror("accept");
 167                 goto error;
 168         }
 169
 170         return new_fd;
 171
 172 error:
 173         return -1;
 174 }
 175
 176 /*
 177  *      ustcomm_create_unix_sock
 178  *
 179  *      Creates a AF_UNIX local socket using pathname
 180  *      bind the socket upon creation and return the fd.
 181  */
 182 int ustcomm_create_unix_sock(const char *pathname)
 183 {
 184         struct sockaddr_un sun;
 185         int fd;
 186         int ret = -1;
 187
 188         /* Create server socket */
 189         if ((fd = socket(PF_UNIX, SOCK_STREAM, 0)) < 0) {
 190                 perror("socket");
 191                 goto error;
 192         }
 193
 194         memset(&sun, 0, sizeof(sun));
 195         sun.sun_family = AF_UNIX;
 196         strncpy(sun.sun_path, pathname, sizeof(sun.sun_path));
 197         sun.sun_path[sizeof(sun.sun_path) - 1] = '\0';
 198
 199         /* Unlink the old file if present */
 200         (void) unlink(pathname);
 201         ret = bind(fd, (struct sockaddr *) &sun, sizeof(sun));
 202         if (ret < 0) {
 203                 perror("bind");
 204                 goto error;
 205         }
 206
 207         return fd;
 208
 209 error:
 210         return ret;
 211 }
 212
 213 /*
 214  *      ustcomm_listen_unix_sock
 215  *
 216  *      Make the socket listen using LTTNG_UST_COMM_MAX_LISTEN.
 217  */
 218 int ustcomm_listen_unix_sock(int sock)
 219 {
 220         int ret;
 221
 222         ret = listen(sock, LTTNG_UST_COMM_MAX_LISTEN);
 223         if (ret < 0) {
 224                 perror("listen");
 225         }
 226
 227         return ret;
 228 }
 229
 230 /*
 231  *      ustcomm_recv_unix_sock
 232  *
 233  *  Receive data of size len in put that data into
 234  *  the buf param. Using recvmsg API.
 235  *  Return the size of received data.
 236  */
 237 ssize_t ustcomm_recv_unix_sock(int sock, void *buf, size_t len)
 238 {
 239         struct msghdr msg = { 0 };
 240         struct iovec iov[1];
 241         ssize_t ret = -1;
 242
 243         iov[0].iov_base = buf;
 244         iov[0].iov_len = len;
 245         msg.msg_iov = iov;
 246         msg.msg_iovlen = 1;
 247
 248         ret = recvmsg(sock, &msg, 0);
 249         if (ret < 0) {
 250                 perror("recvmsg");
 251         }
 252
 253         return ret;
 254 }
 255
 256 /*
 257  *      ustcomm_send_unix_sock
 258  *
 259  *      Send buf data of size len. Using sendmsg API.
 260  *      Return the size of sent data.
 261  */
 262 ssize_t ustcomm_send_unix_sock(int sock, void *buf, size_t len)
 263 {
 264         struct msghdr msg = { 0 };
 265         struct iovec iov[1];
 266         ssize_t ret = -1;
 267
 268         iov[0].iov_base = buf;
 269         iov[0].iov_len = len;
 270         msg.msg_iov = iov;
 271         msg.msg_iovlen = 1;
 272
 273         /*
 274          * Using the MSG_NOSIGNAL when sending data from sessiond to
 275          * libust, so libust does not receive an unhandled SIGPIPE or
 276          * SIGURG. The sessiond receiver side can be made more resilient
 277          * by ignoring SIGPIPE, but we don't have this luxury on the
 278          * libust side.
 279          */
 280         ret = sendmsg(sock, &msg, MSG_NOSIGNAL);
 281         if (ret < 0) {
 282                 perror("sendmsg");
 283         }
 284
 285         return ret;
 286 }
 287
 288 /*
 289  *  ustcomm_close_unix_sock
 290  *
 291  *  Shutdown cleanly a unix socket.
 292  */
 293 int ustcomm_close_unix_sock(int sock)
 294 {
 295         int ret;
 296
 297         /* Shutdown receptions and transmissions */
 298         ret = shutdown(sock, SHUT_RDWR);
 299         if (ret < 0) {
 300                 perror("shutdown");
 301         }
 302
 303         return ret;
 304 }
 305
 306 /*
 307  *  ustcomm_send_fds_unix_sock
 308  *
 309  *  Send multiple fds on a unix socket.
 310  */
 311 ssize_t ustcomm_send_fds_unix_sock(int sock, void *buf, int *fds, size_t nb_fd, size_t len)
 312 {
 313         struct msghdr msg = { 0 };
 314         struct cmsghdr *cmptr;
 315         struct iovec iov[1];
 316         ssize_t ret = -1;
 317         unsigned int sizeof_fds = nb_fd * sizeof(int);
 318         char tmp[CMSG_SPACE(sizeof_fds)];
 319
 320         /*
 321          * Note: the consumerd receiver only supports receiving one FD per
 322          * message.
 323          */
 324         assert(nb_fd == 1);
 325
 326         msg.msg_control = (caddr_t)tmp;
 327         msg.msg_controllen = CMSG_LEN(sizeof_fds);
 328
 329         cmptr = CMSG_FIRSTHDR(&msg);
 330         cmptr->cmsg_level = SOL_SOCKET;
 331         cmptr->cmsg_type = SCM_RIGHTS;
 332         cmptr->cmsg_len = CMSG_LEN(sizeof_fds);
 333         memcpy(CMSG_DATA(cmptr), fds, sizeof_fds);
 334         /* Sum of the length of all control messages in the buffer: */
 335         msg.msg_controllen = cmptr->cmsg_len;
 336
 337         iov[0].iov_base = buf;
 338         iov[0].iov_len = len;
 339         msg.msg_iov = iov;
 340         msg.msg_iovlen = 1;
 341
 342         ret = sendmsg(sock, &msg, 0);
 343         if (ret < 0) {
 344                 perror("sendmsg");
 345         }
 346
 347         return ret;
 348 }
 349
 350 int ustcomm_send_app_msg(int sock, struct ustcomm_ust_msg *lum)
 351 {
 352         ssize_t len;
 353
 354         len = ustcomm_send_unix_sock(sock, lum, sizeof(*lum));
 355         switch (len) {
 356         case sizeof(*lum):
 357                 printf("message successfully sent\n");
 358                 break;
 359         case -1:
 360                 if (errno == ECONNRESET) {
 361                         printf("remote end closed connection\n");
 362                         return 0;
 363                 }
 364                 return -1;
 365         default:
 366                 printf("incorrect message size: %zd\n", len);
 367                 return -1;
 368         }
 369         return 0;
 370 }
 371
 372 int ustcomm_recv_app_reply(int sock, struct ustcomm_ust_reply *lur,
 373                           uint32_t expected_handle, uint32_t expected_cmd)
 374 {
 375         ssize_t len;
 376
 377         memset(lur, 0, sizeof(*lur));
 378         len = ustcomm_recv_unix_sock(sock, lur, sizeof(*lur));
 379         switch (len) {
 380         case 0: /* orderly shutdown */
 381                 printf("Application has performed an orderly shutdown\n");
 382                 return -EINVAL;
 383         case sizeof(*lur):
 384                 printf("result message received\n");
 385                 if (lur->handle != expected_handle) {
 386                         printf("Unexpected result message handle\n");
 387                         return -EINVAL;
 388                 }
 389
 390                 if (lur->cmd != expected_cmd) {
 391                         printf("Unexpected result message command\n");
 392                         return -EINVAL;
 393                 }
 394                 if (lur->ret_code != USTCOMM_OK) {
 395                         printf("remote operation failed with code %d.\n",
 396                                 lur->ret_code);
 397                         return lur->ret_code;
 398                 }
 399                 return 0;
 400         case -1:
 401                 if (errno == ECONNRESET) {
 402                         printf("remote end closed connection\n");
 403                         return -EINVAL;
 404                 }
 405                 return -1;
 406         default:
 407                 printf("incorrect message size: %zd\n", len);
 408                 return len > 0 ? -1 : len;
 409         }
 410 }
 411
 412 int ustcomm_send_app_cmd(int sock,
 413                         struct ustcomm_ust_msg *lum,
 414                         struct ustcomm_ust_reply *lur)
 415 {
 416         int ret;
 417
 418         ret = ustcomm_send_app_msg(sock, lum);
 419         if (ret)
 420                 return ret;
 421         ret = ustcomm_recv_app_reply(sock, lur, lum->handle, lum->cmd);
 422         if (ret)
 423                 return ret;
 424         return 0;
 425 }
 426
 427
 428 /*
 429  * Receives a single fd from socket.
 430  *
 431  * Returns the size of received data
 432  */
 433 int ustcomm_recv_fd(int sock)
 434 {
 435         struct iovec iov[1];
 436         int ret = 0;
 437         int data_fd;
 438         struct cmsghdr *cmsg;
 439         char recv_fd[CMSG_SPACE(sizeof(int))];
 440         struct msghdr msg = { 0 };
 441         union {
 442                 unsigned char vc[4];
 443                 int vi;
 444         } tmp;
 445         int i;
 446
 447         /* Prepare to receive the structures */
 448         iov[0].iov_base = &data_fd;
 449         iov[0].iov_len = sizeof(data_fd);
 450         msg.msg_iov = iov;
 451         msg.msg_iovlen = 1;
 452         msg.msg_control = recv_fd;
 453         msg.msg_controllen = sizeof(recv_fd);
 454
 455         printf("Waiting to receive fd\n");
 456         if ((ret = recvmsg(sock, &msg, 0)) < 0) {
 457                 perror("recvmsg");
 458                 goto end;
 459         }
 460         if (ret != sizeof(data_fd)) {
 461                 printf("Received %d bytes, expected %ld", ret, sizeof(data_fd));
 462                 goto end;
 463         }
 464         cmsg = CMSG_FIRSTHDR(&msg);
 465         if (!cmsg) {
 466                 printf("Invalid control message header\n");
 467                 ret = -1;
 468                 goto end;
 469         }
 470         if (cmsg->cmsg_level != SOL_SOCKET || cmsg->cmsg_type != SCM_RIGHTS) {
 471                 printf("Didn't received any fd\n");
 472                 ret = -1;
 473                 goto end;
 474         }
 475         /* this is our fd */
 476         for (i = 0; i < sizeof(int); i++)
 477                 tmp.vc[i] = CMSG_DATA(cmsg)[i];
 478         ret = tmp.vi;
 479         printf("received fd %d\n", ret);
 480 end:
 481         return ret;
 482 }